Spinning solution and process for making same



Patented Nov. 6, I934 PATENT OFFICE SPINNING SOLUTION AND PROCESS FOR MAKING SAME Johan D. W. Hubbeling, Enka, N. 0., assignor to American Enka Corporation, Enka, N. 0., a corporation of Delaware No Drawing. Application December 6, 1933, Serial No. 701,238

2 Claims.

Thisinvention relates to an improved cellulosic spinning solution, more particularly one in which delustering agents are employed.

To reduce the lustre of artificial silk filaments it is known to employ various oils and/or inorganic pigments. These agents may, if desired, be incorporated in the filament after it has been extruded through the spinnerette. However, it has been found that better results are obtained by introducing the oils and/or pigments into the solution prior to spinning.

In carrying out such a process a rather difficult problem presented itself in that an even and uniform dispersion of the oils and/or pigments could not be had. At the present time this problem has been solved, and to a large extent very satisfactory results have been obtained.

The term oils is meant to include those types of oils which are immiscible with the spinning solution.

In the past it has been the practice to first introduce an immiscible oil in the spinning solution and thereafter, in a separate operation, suspending a pigment in a dispersing agent.

5 The dispersing agent was a type of oil such as monopol oil that is miscible with the spinning solution. This suspension was then introduced into the spinning solution immiscible oil mix A ture and thoroughly dispersed.

Upon carrying out the above described process and later extruding this solution through the minute apertures of the spinnerettes, it was found that over a very short period of time about 70% of these apertures became clogged thereby decreasing the quality of the yarn, and involving a considerable expense and loss of time consumed in cleaning the spinnerettes.

To determine the underlying cause for this high degree of clogged spinnerettes, a micro- 40, scopic examination was performed on the spinning solution. It was found that the pigment particles, incorporated within the spinning solution in the form of an oil-pigment suspension, were located within the globules of the immiscible oil.

Further investigation of the ring formation, that formed in and caused the clogging of the apertures of the spinnerettes, showed deposits of the pigments employed. Theoretically, basing 50. the cause of this pigment formation on the manner in which pigment particles had been dispersed within the oil globules, it was assumed that the trouble resided in the reagents intro duced into the cellulosic solution.

By the present invention the clogging of spinnerettes has been materially reduced and a more uniform and homogeneous spinning solution has been produced.

It is therefore the object of the present invention to produce an improved cellulosic spinning solution which will not, during the spinning operation, result in an appreciable percent of clogged spinnerettes.

It is a further object to provide a more homogeneous and evenly dispersed pigment-oil-spinning solution mixture, wherein the pigment dispersion and immiscible oil dispersion is maintained completely separated and independent.

A still further object is the provision of a novel method of forming a dull lustre cellulosic solution.

According to the present invention a cellulosic solution such as viscose is employed. This viscose is a cellulose xanthate solution dissolved in sodium hydroxide containing about 6% to 8 cellulose and approximately 7% alkali of which 4% is free sodium hydroxide.

An immiscible, relatively volatile and non saponifiable oil or mixture of such oils is first introduced and thoroughly dispersed into the viscose solution. One such oil which has been found to produce excellent results is pine oil.

A pigment suspension is next made by first preparing a paste of the pigment and a solution of sodium hydroxide and then the paste is diluted with a larger amount of sodium hydroxide to form a suspension, the NaOI-I content is always higher than that in the spinning solution. The suspension is transferred to a high speed mixer and stirred for about an hour. One example of a very satisfactory suspension which has been used is: 640 grams of smog added to 500 cc. of an 8% NaOH solution, this being mixed to form a paste and later diluted with 2000 cc. of an 8% NaOI-I solution to form a uniform suspension. This suspension is added to the viscose-oil mixture and stirred for about two hours.

Such a procedure forms a spinning solution which may be extruded through spinnerettes in a very satisfactory manner and results in reducing the number of clogged spinnerettes to an almost negligible amount.

Upon miscroscopic examination of this solution it is determined that the pigment particles exist in an entirely separate and independent dispersion from the immiscible oil globules. In other words the pigment particles are found to be on the outside of the oil globules and therefore form a very much more homogeneous and uniform dispersion. The reason for this is that the dispersion of the pigment particles is not dependent on the dispersion of the oil globules as it had been when the pigment had been incorporated by using monopol oil as the suspending agent.

From this it can clearly be seen that a spinning solution, having at least two. distinct advantages over prior solutions, has been formed.

Whereas the term pigment particles in general has been employed throughout the specification, this term is meant to include that type of inert inorganic pigment such as oxides of tin', titanium or BaSO4 and the like.

Although the process has been described. us.-

ing sodium hydroxide as the dispersing agent,

. cellulosic spinning solution which comprises, disother strong bases may be employed if desired. It has further been found that "to substitute press lye for NaOI-I will result in separate dis persion of the pigment and immiscible oil. This press lye contains essentially sodium hydroxide and hemicellulose and is a bi-product during the the treatment of the alkali cellulose with the the solution an oil and subsequently introducing into said solution a pigment which has previously been suspended; in an alkaline reagent consisting of Water and alkali.

2. The method. of producing an improved persing. an immiscible oil in the solution, and subsequently efiecting a separate dispersion of a pigment in the solution by introducing into the solution an aqueous suspension of a pigment in an alkali whereby the said separate pigment dispersion forms within the solution on the outside of the oil globules.

JOHAN D. w. l-IU'BBELING. 

